An inguinal hernia is a condition where a small loop of bowel or intestine protrudes through a weak place or defect within the lower abdominal muscle wall or groin of a patient. This condition commonly occurs in humans, particularly males. Hernias of this type can be a congenital defect wherein the patient is born with this problem, or can be caused by straining or lifting heavy objects. Heavy lifting may be known to create a large amount of stress upon the abdominal wall and can cause a rupture or tearing at a weak point of the abdominal muscle to create the defect or opening. In any case, the patient can be left with an unsightly bulge of intestinal tissue protruding through the defect, pain, reduced lifting abilities, and in some cases, impaction of the bowel, or possibly other complications if the flow of blood is cut off to the protruding tissue.
A common solution to this problem can be surgery. In the surgical procedure, the defect is accessed and carefully examined, either through an open incision or endoscopically through an access port such as a trocar. In either case, the careful examination can be well appreciated, as a network of vessels and nerves exist in the area of a typical defect, which requires a surgeon to conduct a hernia repair with great skill and caution. Within this area can be found vascular structures such as gastric vessels, the external iliac vessels, and the inferior epigastric vessels, and reproductive vessels such as the vas deferens extending through the inguinal floor.
Once the surgeon is familiar with the anatomy of a patient, the surgeon carefully pushes the bowel back into the patient's abdomen through the defect. Repairing the defect can involve closure of the defect with sutures or fasteners but generally involves placing a surgical prosthetic such as a mesh patch over the open defect, and attaching the mesh patch to the inguinal floor with conventional suture or with surgical fasteners. The mesh patch acts as a barrier and prevents expulsion of bowel through the defect. Suturing of the mesh patch to the inguinal floor can be well suited to open procedures but can be much more difficult and time consuming with endoscopic procedures. With the adoption of endoscopic surgery, endoscopic surgical instruments that apply surgical fasteners can be used. However, the tissue of the inguinal floor may offer special challenges to the surgeon when a needle or fastener is used to penetrate structures such as Cooper's ligament.
At present, there are a variety of surgical instruments and fasteners available for the surgeon to use in an endoscopic or open procedure to attach the mesh patch to the inguinal floor. One of the earliest types of endoscopic surgical instruments used is a surgical stapler. A plurality or stack of these unformed staples may be generally contained within a stapling cartridge in a serial fashion, and may be sequentially advanced or fed within the instrument by a spring mechanism. A secondary valving or feeding mechanism may be employed to separate the distal most staple from the stack, to hold the remainder of the spring loaded stack, and may be used to feed the distal most stapler into the staple forming mechanism. Feeding mechanisms of this type are found in U.S. Pat. No. 5,470,010 by Robert Rothfuss et al. and in U.S. Pat. No. 5,582,616, also by Robert Rothfuss et al.
Another hernia mesh attachment instrument uses a helical wire fastener that resembles a small section of spring. Multiple helical wire fasteners may be stored serially within the 5 mm shaft, and may be corkscrewed or rotated into tissue. A load spring may be used to bias or feed the plurality of helical fasteners distally within the shaft. A protrusion extends into the shaft to possibly prevent the ejection of the stack of fasteners by the load spring and may permit passage of a rotating fastener. Instruments and fasteners of these types are found in U.S. Pat. No. 5,582,616 by Lee Bolduc et al., U.S. Pat. No. 5,810,882 by Lee Bolduc et al., and in U.S. Pat. No. 5,830,221 by Jeffrey Stein et al.
Whereas the above surgical instruments may be used for hernia fastening applications, they use a spring mechanism to feed a plurality of fasteners through the surgical instrument. Spring mechanisms typically use a long soft coil spring to push a stack of fasteners through a guide or track within the shaft of the surgical instrument. These types of feeding mechanisms may be generally simple and reliable, but may require an additional secondary valving mechanism or protrusion to separate and feed one fastener from the stack.
Other surgical fasteners may be used for hernia mesh attachment but utilize either a reloadable single shot instrument or a rotary magazine that holds a small number of fasteners. These types of surgical fastening instruments can be found in U.S. Pat. No. 5,203,864 and U.S. Pat. No. 5,290,297 both by Edward Phillips. These instruments have not gained acceptance by the surgical community, possibly due to their single shot capabilities and the large size of the rotary magazine, which can restrict such an instrument to an open procedure.
Whereas all the above surgical instruments may be used for hernia fastening applications, they either use a spring mechanism to feed the plurality of fasteners through the surgical instrument, or a rotary magazine in lieu of a feeding mechanism. Other types of surgical fasteners may be available, such as surgical clips, and they can utilize feeding mechanisms that do not require the use of a spring to feed the clips distally. A reciprocating feeding mechanism is described in U.S. Pat. No. 5,601,573 U.S. Pat. No. 5,833,700, and U.S. Pat. No. 5,921,997 by Fogelberg et al. Fogelberg et al. teaches a clip applier with a feeding mechanism that utilizes a reciprocating feed bar to feed a serial stack of clips. A feeder shoe may operably engage with and move with the distally moving feed bar and may slidingly engages with the proximally moving feed bar. Thus, the feeder shoe may index or push the stack of clips distally with the distally moving feed bar and remains stationary relative to the proximally moving feed bar. A valving mechanism may be also required to separate the distal most clip from the stack and to hold the stack stationary as the distal most clip may be applied onto a vessel. Whereas Fogelberg et al. teaches a reciprocating feeding mechanism with a single reciprocating member, he does not teach the use of the clip applier in the attachment of hernia mesh, nor does he teach the individual driving or feeding of each clip by a moving member.
Another fastener feeding mechanism that uses reciprocation is that disclosed in U.S. Pat. No. 4,325,376 by Klieman et al. A clip applier that stores a plurality of clips in a serial fashion within a clip magazine is disclosed. The clips are in a stack wherein the proximal most clip may be pushed or fed distally by a pawl that may be ratcheted or indexed distally by a reciprocating member or ratchet blade with each actuation of the instrument. As the pawl indexes distally, it can push the stack of clips distally. A secondary valving mechanism may be also described. Thus, the feeding mechanism of Klieman et al. teaches the use a single reciprocating member and pawl to push or feed the stack of clips distally, and may require a secondary valving mechanism to feed the distal most clip.
U.S. Pat. No. 3,740,994 by DeCarlo Jr. describes a novel reciprocating feeding mechanism that may index a plurality of staples or clips, and may ready them for discharge by reciprocating one of a pair of opposing leaf spring assemblies. The staples reside serially within a guide rail with a fixed leaf spring assembly extending into the plane of the guide rail. A reciprocating leaf spring assembly may opposedly extend inwardly towards the fixed leaf spring assembly. As the a reciprocating leaf spring assembly moves distally, each of individual leaf springs of the assembly may engage a staple and move it distally. The distally moving plurality of staples deflect the local individual leaf springs of the fixed leaf spring assembly, and the deflected leaf springs may return to the un-deflected position after passage of the staple. As the moving leaf spring assembly moves proximally, the leaf springs of the fixed leaf spring assembly hold the staples stationary and prevent distal movement thereof. A secondary guide rail and valving mechanism may be provided to separate a single staple from the stack for forming and can hold the stack of staples stationary as the single clip is formed.
Additionally, similar feeding mechanisms are disclosed in U.S. Pat. No. 4,478,220 by Di Giovanni et al. and U.S. Pat. No. 4,471,780 by Menges et al. Both of these related patents teach a reciprocating feeding mechanism that uses one fixed member and one reciprocating member to feed or index a plurality of clips distally. Angled flexible fingers may be hingedly attached to the reciprocating member and operatively engage the clips when moving distally, and slidingly engage with the clips when moving proximally. The angled flexible fingers within the fixed member deflect out of the way when the clips move distally and spring up to stop proximal movement of the clip after the clip has passed. A secondary valving mechanism is also disclosed.
Thus, the feeding mechanism of DeCarlo et al., Di Giovanni et al., and Menges et al. operatively engage and individually move each clip distally between a single reciprocating member and a fixed member. However each instrument may require a secondary valving mechanism for the feeding and forming of the distal most clip.
The majority of the feeding mechanisms described above can require two feeding mechanisms; a primary feeding mechanism to feed a plurality of clips distally, and a secondary valving or feeding mechanism to separate and feed the distal most fastener while preventing the distal movement of the remaining fasteners. Such additional mechanisms may be costly and increase the size or diameter of the instrument size. Likewise, the single shot or rotary magazines may have limitations. What may be needed is an improved reciprocating feeding mechanism that may not require the use of a secondary valving mechanism, and may simultaneously engage with and independently drive each fastener distally. Such a mechanism can have two reciprocating members and could provide superior advantages such as lower cost, reduced complexity, and a smaller diameter shaft.